Cyanoethylation is a well known chemical reaction involving the addition of acrylonitrile to an inorganic or organic compound containing a labile hydrogen atom. Cyanoethylation reactions are disclosed, for example in Organic Reactions, Vol. V, Chapter 2 (John Wiley & Sons, New York, 1949) and The Chemistry of Acrylonitrile (American Cyanamide Company, 1959), both of which disclosures are incorporated herein by reference. However, attempts to prepare the cyanoethylation product of maleimide by the reaction of maleimide and acrylonitrile have been unsuccessful.
On the other hand, the Searle U.S. Pat. No. 2,444,536 discloses a process for the synthesis of N-arylmaleimides wherein an aryl maleamic acid is treated with acetic anhydride in the presence of fused sodium acetate at a temperature of 80.degree. to 100.degree. C. However, Searle provides no teaching relating to the preparation of N-propionitrile maleimides.